Cooling installation for piston internal combustion engines

ABSTRACT

A cooling circulation system for piston internal combustion engines with a cooling jacket and a control system which interrupts the cooling medium circulation through the cooling jacket at least within the area of the combustion zones up to a first predetermined limit value of the temperature of the engine and/or of the time after the start of the engine, which above the first predetermined limit value at first limits the same to a closed circulation in by-passing relationship to a radiator and avoiding fresh water exchange, and which above a second further predetermined limit value incorporates into the cooling medium circulation the radiator, a heater-heat-exchanger and/or the fresh water exchange; the control system thereby includes a cooling medium valve and a three-way thermostat each with a separate control element, for example, in the form of an expansion element, of which the cooling medium valve is actuated upon reaching the first limit value and the three-way thermostat upon reaching the second limit value.

Waite t Mayr et a1.

;; atent [191 [451 Dec. 3, 1974 COOLING INSTALLATION F OR PISTON INTERNAL COMBUSTION ENGINES [73] Assignee: Bayerische Motoren Werke Aktiengesellschaft, Munich, Germany [22] Filed: Feb. 9, 1973 [21] App]. No.: 331,036

[30] Foreign Application Priority Data Feb. 10, 1972 Germany 2206266 [52] 11.8. C1 123/4108, 123/4102, 123/4109, 236/345, 237/12.3 B [51] Int. Cl. FOlp 7/14 [58] Field of Search 123/4'1.1, 41.08, 41.09, 123/4102; 236/345; 237/12.3 B, 12.3 R

[56] References Cited UNITED STATES PATENTS 1,328,855 l/1920 Sweet 123/4108 1,767,598 6/1930 Mallory... 236/34.5 1,848,987 3/1932 Anibal l23/4l.l 2,038,193 4/1936 Parsons 237/12.3 2,086,440 7/1937 Rushmore... l23/4l.08 2,445,684 7/1948 Mallory 123/4108 1 2,468,735 5/1949 Brubaker.... l23/4l.08 2,706,085 4/1955 Nallinger 237/8 2,749,049 6/1956 Smith 237/l2.3 B

3,211,374 10/1965 Matulaitis 237/l2.3 B 3,313,483 4/1967 Nallinger 236/345 FOREIGN PATENTS OR APPLICATIONS 421,701 12/1934 Great Britain 123/4108 Primary Examiner-Manuel A. Antonakas Assistant Examiner-Daniel J. OConnor Attorney, Agent, or Firm-Craig & Antonelli [57] ABSTRACT A cooling circulation system for piston internal combustion engines with a cooling jacket and a control system which interrupts the cooling medium circulation through the cooling jacket at least within the area of the combustion zones up to a first predetermined limit value of the temperature of the engine and/or of the time after the start of the engine, which above the first predetermined limit value at first limits the same to a closed circulation in by-passing relationship to a radiator and avoiding fresh water exchange, and which above a second further predetermined limit value incorporates into the cooling medium circulation the radiator, a heater-heat-exchanger and/or the fresh water exchange; the control system thereby includes a cooling medium valve and a three-way thermostat each with a separate control element, for example, in the form of an expansion element, of which the cooling medium valve is actuated upon reaching the first limitvalue and the three-way thermostat upon reaching the second limit value.

41 Claims, 9 Drawing Figures SHEET 10F 6 PATENTEL DEC 3 I974 PATENTELBEE 31914 385L629 SHEET 30F 6 Fig. 3

PATENTELUEB 31914 3.851.629

SHEET H1! 6 COOLWG INSTALLATION FOR PHSTON HNTERNAL COMBUSTION ENGINES The present invention relates to a circulatory cooling installation for piston internal combustion engines with a cooling jacket and a control mechanism which interrupts the cooling medium circulation at least within the area of the combustion zones up to a first predetermined limited value of the temperature of the engine and/or of the time after the starting of the engine, above the first predetermined limit value then limits at first the circulation to a closed circulation in by-passing a radiator and avoiding a fresh water exchange, and above a further predetermined limit value includes in the cooling medium circulation the radiator, a heater heat-exchanger and/or the fresh water exchange.

Such a type of construction is already described in the US. Pat. No. 2,706,085 whereby the control system consists of a bellows thermostat and of one of several slide valves. However, such a construction cannot solve satisfactorily the intended purpose of such a control system. A bellows thermostat is applicable to customary modern excess pressure cooling systems only to a very limited and conditional extent by reason of its pressure sensitivity. Slide valves with a reasonable and acceptable expenditure do not exhibit a sufficient sealing tightness requisite particularly in the existing application. The exchange of these structural elements with customary modern control elements such as, in particular, expansion elements and disk valves, however, is not readily possible because, on the one hand, a very large path or travel of the control element is necessary and, on the other, several control openings have to be controlled one after the other.

A cooling system is described in the German Offenlegungsschrift No. 2,061,762 in which, for purposes of achieving good running properties of .the engine under different load conditions, the through-passage of fresh water is limited below the limit value to a first area of the cooling jacket outside of the combustion zones with a throttled flow. The overflow of the cooling medium into a second area of the combustion zones is controlled by means of valves in dependence on the temperature of the cooling medium after the passage through the first area. As a result thereof, the temperature of the engine is to be adjusted in the second area of the cooling jacket to high values also at low loads, however, the temperature in the first area of the cooling jacket cannot be uniformly controlled with changing loads of the engine. Instead, at a low load an undercooling of the engine in the first area of the cooling jacket is unavoidable as a result of the low inlet temperature of the cooling medium consisting of fresh water. Also, a non-uniform temperature distribution exists in the engine because cold fresh water always is efiective at the cooling medium inlet which heats up on its way to the discharge at another place provided with the control valves. For this reason, a separate special flow guidance in the cooling jacket with an expensive construction of the engine parts is necessary in that case and thus an application in existing engine types having an uncontrolled overflow of the cooling medium between the first and the second area of the cooling jacket is not possible. Since additionally exclusively a control of the temperature of the cooling medium at the overflow between the two areas of the cooling jacket takes place in this case, an accurate control of the temperature of the cooling medium in the second area of the cooling jacket is not possible. Instead, a low control temperature has to be selected in the inlet to this area to avoid an overheating whereby again most favorable combustion conditions in the combustion spaces cannot be attained under allload conditions of the engine.

, It is the aim of the present invention to provide a control installation which makes it possible with the use of customary modern structural elements, such as, for example, expansion elements and disk valves, to bring or raise in a short time from the cold start of the engine the temperature thereof, especially in the combustion zones, to most favorable values with a far-reaching uni form temperature distribution in the entire cooling jacket. Starting with the known recognition (German Offenlegungsschrift No. 2,123,360) that the emission of harmful exhaust gas components is low at high engine temperature, and utilizing the slight heat transfer to a non-moving cooling medium, above all the walls of the combustion zones, especially the walls of the combustion spaces and of the gas-exchange channels in the cylinder head of reciprocating piston engines or the hot housing casing zones of rotary piston internal combustion engines are to reach the desired operating temperatures in as short as possible a period of time by means of the stationary cooling medium, i.e., which is standing still at least in the second area of the cooling jacket during the warm-up period. Only a slight, unavoidable temperature difference between the inlet and discharge places of the cooling jacket is thereby to occur inside of the engine, preferably by circulation controls for the circulation of the cooling medium.

The underlying problems are solved according to the present invention in that the control system includes a cooling medium valve and a conventional three-way thermostat, with a separate control element each, of which the cooling medium valve is actuated after reaching the first limit value and the three-way thermostat is actuated after reaching the further limit value.

Such a control of the cooling medium circulatory systems limits, with the possibility of the utilization of one commercially available double-acting and single-acting thermostat each, the emission of harmful exhaust gas components which during the warming-up period of the engine is increased by reason of the fuel enrichment necessary thereby,"to a considerably shortened period of time since the walls of the combustion zones reach rapidly the operating temperature for the most favorable combustion conditions. The over-all emission of harmful exhaust gas components is reduced thereby particularly in residential and high-density traffic areas since, for the most part, it is there that the engines of motor vehicles are started and driven during warm-up.

Though it is already disclosed in the German Offenlegungsschrift No. 2,123,360 for the same purpose to heat-up more rapidly the cooling medium of internal combustion engines by a heater device during the starting and warm-up operation, nonetheless a very high structural expenditure and an additional oxygen requirement as well as an additional discharge of exhaust gases are inherent to such prior art device. In contrast to the present invention, this prior art proposal therefore satisfies the task of avoiding harmful exhaust gas components only to a very limited extent.

Numerous possibilities exist for the actual construction of the present invention as will become apparent from the following description and the appended claims. For the rapid warm-up of the cooling medium in the engine, in lieu of a cooling medium valve for interrupting the entire cooling medium circulation, a cooling medium pump may be provided which is adapted to be stopped up to a predetermined limit value. This cooling medium pump may be controlled as a function of time as also as a function of the temperature of the cooling medium or of a structural part within the second area of the cooling jacket.

These and further objects, features and advantages of the present invention will becomemore apparent from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, several embodiments in accordance with the present invention, and wherein:

FIG. 1 is a schematic view of a cooling system for an internal combustion engine in accordance with the present invention;

FIGS. 2a, 2b and 2c are schematic views illustrating the operation of the cooling system according to FIG. 1 in three phases;

FIG. 3 is a diagram illustrating the temperature rise as a function of warming-up time of an' internal combustion engine with and without the construction of the cooling system according to the present invention;

FIGS. 4a and 4b are a longitudinal and transverse cross-sectional view through a three-way thermostat with a cooling medium valve in a structural unit according to the present invention, the cross section of FIG. 4a being taken along line lVa-IVa of FIG. 4b and the cross section of FIG. 4b being taken along line IV- bIVb of FIG. 4a;

FIG. 5 is a schematic view, similar to FIG. 1, of a modified embodiment of the arrangement of the threeway thermostat with a cooling medium valve as a structural unit in accordance with the present invention, and

FIG. 6 is a schematic view, similar to FIG. 1, of a modified embodiment showing the addition of return line 35.

Referring now to the drawing wherein like reference numerals are used throughout the various views to designate like parts, and more particularly to FIG. 1, this figure illustrates in schematic view the cooling system of an internal combustion engine generally designated by reference numeral 1. The cooling jacket of the internal combustion engine 1 which is constructed in a conventional manner includes a first area or zone 2 which is arranged in the cylinder block of the engine 1 and encloses essentially the cylinder sliding surfaces of the pistons of the engine. A second area or zone 3 of the cooling jacket is arranged in the cylinder head of the engine 1 and encloses above all the combustion zones, namely, the combustion spaces as well as the gasexchange channels.

For the circulation of the cooling medium, the engine 1 includes at the usual places a cooling medium inlet aperture 4 into the first area 2 of the cooling jacket at a low location and a cooling medium outlet or discharge aperture 5 out of the second area 3 of the cooling jacket at a high location. An additional discharge aperture 6 out of the first area 2 is arranged at a place adjacent the inlet aperture 4. Finally, still a further high discharge aperture 7 out of the second area 3 of the cooling jacket may be provided.

A free, unobstructed cooling medium line 8 leads from the discharge aperture 5 to a radiator 9. The coolingrnedium line 8 includes a branch place 1t] from which branches off a by-pass 11 which by-passes the radiator 9 and which terminates at a mixing place 14 in the return line 13 leading from the radiator 9 to a cooling medium pump 12 and to the inlet aperture 4. The mixing place 14 includes a three-way thermostat 15 with one disk valve 16 and 17 each for the alternate control of the cooling medium inlet out of the bypass 11 and out of the return line 13 into the continuation of the return line 13 to the cooling medium pump 12 and to the inlet aperture 4. An expansion element 18 located in the mixing place 14 between the disk valves 16 and 17 is present for the control of the three-way thermostat 15.

A circulation line 19 leads from the additional discharge aperture 6 out of the first area 2 of the cooling jacket by way of a heater heatexchanger 20 and a cooling medium valve 21 into the return line 13 and further by way of the cooling medium pump 12 into the inlet aperture 4. The cooling medium valve 21 also includes a disk valve 22 and an expansion element 23. This cooling medium valve 21 closes the portion of the return line 13 which connects the mixing place 14 with the cooling medium pump 12, up to a predetermined temperature of the cooling medium flowing through the circulation line 19. A parallel circulation line 24 branches off from the circulation line 19 between the additional discharge aperture 6 and the heater heatexchanger 20 and terminates again in the circulation line 19 upstream of the cooling medium valve 21. A heater jacket 25 for a suction line throttle valve 26 as well as' a temperature pick-up or transmitter 27 for a conventional fuel metering system of the engine are disposed in this parallel circulation line 24.

The operation of the cooling system of FIG. 1 is as follows:

As can be seen in particular from FIGS. 2a, 2b and 2c, with a cold engine and therewith with a cold cooling medium, the disk valve 22 of the cooling medium valve 21 is closed (FIG. 2a) so that no cooling medium can flow from the discharge aperture 5 to the cooling medium pump 12. As a result thereof, the cooling medium remains stationary or stands still in the second area 3 of the cooling jacket of the engine 1 so that a reduced heat transfer takes place thereat from the walls of the combustion spaces and gas-exchange channels arranged thereat to the cooling medium. Since therebeyond the cooling medium which is present in the cooling medium lines from the discharge aperture 5 up to the disk valve 22 of the cooling medium valve 21, remains stationary and thus does not partake in the warm-up operation of the engine, a very rapid warm-up of the walls of the combustion spaces to an operating temperature is attained at which favorable combustion conditions as regards both running properties of the engine as also as regards low proportion in harmful exhaust gas components establish themselves in the combustion spaces. Especially cold-starting enrichments of the fuel-air mixture can be eliminated after shorter periods of time.

During this warm-up period of the engine, a closed circulation of the cooling medium by way of the inlet aperture 4 and the discharge aperture 6 disposed near the same encompasses only a portion of the first area 2 of the cooling jacket of the engine 1. Since the warmup of the cooling medium partaking in this closed circulation lies at a fixed and nearly always far-reachingly constant ratio to the warm-up of the cooling medium v in the second area 3 of the cooling jacket, no overheating danger exists in the area 3 of the cooling jacket as demonstrated by exhaustive and conclusive test results, insofar as the expansion element 23 is matched corresponding to these temperature conditions to an opening temperature of correspondingly lower value. If the cooling medium pump 12, as is usual, is driven directly by the engine 1, then at higher rotational speeds of the engine 1 and therewith of the cooling pump 12, there results an increase of the cooling medium portion encompassed by this circulation in the cooling jacket due to the thereby increased cooling medium feed quantity in the closed circulation. At particularly high rotational speeds, this cooling medium movement includes nearly the entire cooling jacket in the first and in the second area 2 and 3. In this manner, local overheating appearances of the engine are precluded during the warm-up period also at extreme loads.

Above the control temperature of the expansion element 23 and thus after the opening of the disk valve 22 of the cooling medium valve 21, the cooling medium also flows through the second area 3 of the cooling jacket out of the discharge aperture 5 by way of the bypass line 11, the opened by-pass disk valve 17 of the three-way thermostat into the mixing place 14 and by way of the return line 13 into an additional closed circulation in by-passing relationship to the radiator 9 (FIG. 2b). The closed circulation of the cooling medium through the circulation line 19 thereby remains preserved far-reachingly unchanged.

During a further warm-up of the cooling medium, namely, upon reaching the control temperature of the expansion element 18 of the three-way thermostat 15, the disk valve 16 opens the return line 13 from the radiator 9 with simultaneous continuous closing of the bypass disk valve 17 for the by-pass line 11. The threeway thermostat 15 thereby controls at the mixing place 14 a cooling medium temperature which represents the most favorable operating temperature for the operation of the engine 1. The closed circulation through the circulation line 19 also remains thereby operable without change with an opened disk valve 22 of the cooling medium valve 21.

Under particularly extreme operating conditions, such as especially at extraordinarily high ambient temperatures, slight air flow through the radiator 9 and high power output of the engine 1, the by-pass disk valve 17 of the three-way thermostat 13 closes the bypass 11 (FIG. 2c) so that apart from the continuing present closed circulation through the circulation line 19 the entire cooling water discharged through the discharge aperture 5 out of the cooling jacket of the engine is conducted to the radiator 9 by way of the cool-.

ing medium line 8 and is then conducted by way of the return line 13, the three-way thermostat 15, the cooling medium valve 21 and the cooling medium pump 12 to the inlet aperture 4. As a result thereof, the highest possible cooling output of the cooling system is attained and an overheating of the engine is practically pre-' eluded.

In the control of the cooling system described above, there exists in addition to the particularly rapid warmup of the walls of the combustion spaces in the second area 3 of the cooling jacket for favorable operating conditions and for slight harmful components in the exhaust gases of the engine, a very uniform temperature distribution in both areas 2 and 3 of the cooling jacket of the engine 1. This is so as always a cooling medium is fed through the inlet aperture 4 to the cooling jacket of the engine 1, which exhibits only a slightly lower temperature than the cooling medium leaving the discharge aperture 5. In this manner a very uniform heat distribution with favorable effects on the structural parts of the engine is assured in this manner on the inside of the engine 1.

The development of the temperature of the walls of the combustion spaces of the engine 1 is plotted against time in the diagram of FIG. 3. In a conventional, thermostat-controlled cooling system, in which during the cold start the cooling medium is set into circulation in the cooling jacket from the beginning, the temperature of the walls of the combustion spaces rises according to curve 28. In a construction of the cooling system according to the present invention, a more rapid rise takes place .according to curve 29 so that an operating temperature T beginning with which favorable combustion conditions exist in the combustion spaces, is reached after a lapse of time t which amounts after the cold start of the engine approximately only to half the time after which according to curve 28 this operating temperature T is reached without the construction according to the present invention. Reference numerals 30 and 31 designate curves according to which the temperature of the cooling medium rises in the second area 3 with and without-a construction according to the present invention, respectively; the curves 32 and 33 are thereby indicative for the first area 2 of the cooling jacket. The shape of these curves illustrates that the warming up of the cooling medium in the cooling jacket during the warm-up of the engine is influenced only insignificantly. A disadvantageous effect of the temperature progress on engine structural parts is precluded, at any rate.

Possible modifications of the construction of the cooling system illustrated and described above are indicated in FIG. 1 in dash lines. Accordingly, there exists the possibility to provide a further disk valve 34 in the cooling medium valve 21, which closes the inlet of the circulation line 19 into the cooling medium valve 21 after the opening of the disk valve 22. It can be achieved thereby that the closed circulation through the circulation line 19 no longer represents a by-pass of the radiator 9 upon reaching the operating temperature of the engine. In order to assure nonetheless the operation of the heater-heat-exchanger 20, which, as is known, also acts as a radiator or cooler, a return line 35 may be provided in this case which terminates uncontrolled in the three-way thermostat 15 between the disk valves 16 and 17 and as a result thereof also influences the expansion element 18 thereof. For the feed of a cooling medium with a particularly high temperature, the cooling medium from the first area 2 or the second area 3 of the cooling jacket may be conducted either selectively or also automatically controlled from the further high discharge aperture 7 out of the second area 3 of the cooling jacket by way of a heating water line 36 and a heating three-way valve 37 to the heatexchanger 20.

A further advantageous embodiment of the present invention resides in combining the cooling medium valve 21 with the three-way thermostat 15 into a structural unit. To that end, the cooling medium line 35 is prerequisite which, according to FIG. 1, terminates between the disk valves 16 and 17 of the three-way thermostat 15 in the latter. The cooling medium valve 21 is thereby dispensed with completely so that the circulation line 19' continues directly in the cooling medium line 35 without branching off and the return line 13 out of the three-way thermostat 15 terminates directly in the cooling medium pump 12. The by-pass disk valve 17 of the three-way thermostat 15 thereby has to assume the operation of the disk valve 22 in the cooling medium valve 21. For that purpose, a further expansion element 38 is provided in the three-way thermostat 15 according to FIGS. 4a and 4b, which up to its control temperature closes off the by-pass 11 by means of the by-pass disk valve 17 in its closing position 17. As a result thereof, up to this control temperature, exclusively a closed cooling medium circulation exists out of the discharge aperture 6 through the cooling medium circulation line 19, the adjoining cooling medium line 35, the three-way thermostat 15' between its two disk valves 16 and 17, the return line 13 and the cooling medium pump 12 to the inlet aperture 4. The operation of the cooling system thus remains unchanged with respect to the cooling system described above.

The internal construction of the three-way thermostat combined with the cooling medium valve is illustrated in detail in FIGS. 4a and 4b. The pipe line 39 represents in FIG. 4b a connection between the cooling medium discharge aperture according to FIG. 1, the branch place and the cooling medium line 8 leading freely to the radiator 9. The by-pass 11 (FIG. 4b) consists also in this case exclusively of a short by-pass section. The housing 40 of the three-way thermostat is constructed in one piece together with the pipe line 39 and has an essentially cylindrical shape, at the two end faces of which are arranged the disk valves 16 and 17. A housing cover 40 enables the assembly of the three-way thermostat 15. The disk valve 17* serves simultaneously as by-pass valve and as cooling medium valve and, for this purpose is left closed as cooling medium valve up to the control temperature thereof, is then opened and is again closed by the expansion element 18 of the three-way thermostat l5, simultaneously with the-opening of the disk valve 16 at the control temperature of the expansion element 18. The expansion element 18 is thereby connected directly with the disk valve 16. The piston rod 18 thereof is supported by way of a curved support member 41 and a valve seat 42 at the housing 40. A cylindrical closure spring 44 is supported at a curved support member 43 which is fixed at the housing 40 by way of the valve seat 42; the closure spring 44 acts on the disk valve 16 in the closing direction. The curved support member 43 carries a pair of centering sheet metal members 45 for the freely projecting end of the expansion element 18. Additionally, the curved support member 43 includes a central guide bore 46 for the also freely projecting end of the expansion element 38. The piston rod 38 of the expansion element 38 is supported at a curved connecting member 47 which is secured at the disk valve 16 and again serves as abutment for a coil compression spring 49 under interconnection of a supporting ring 48; the coil spring 49 acts upon the by-pass disk valve 8 17 in the closing direction. A curved draw member 50 is secured at the by-pass disk valve 17 which encloses the expansion element 38 and is slidingly supported at the latter against an abutment 51 constructed as annular oflset. The housing finally also carries one short connecting pipe stub 13, 13" and 35 each as parts of the cooling medium line 35 and of the return line 13 from the radiator 9 and to the cooling medium pump 12.

With a cold cooling medium, the structural parts of the three-way thermostat 15' assume the position illustrated in FIGS. 4a and 4b. Both the by-pass disk valve 17 in its operation as cooling medium valve as also the disk valve 16 for the return line 13 from the radiator 9 are thereby closed. With a running engine 1 and therewith with a feed of cooling medium by the cooling medium pump 12, a closed circulation of the cooling medium exists through the cooling medium line 35 and the connecting pipe stub 35' thereof at the housing 40 into the interior of the three-way thermostat 15 and through the return line 13 and the connecting pipe stub 13' at the housing 40 back' to the cooling medium pump 12 and thus through a part of the first area 2 of the cooling jacket of the engine 1 between the inlet aperture 4 and the discharge aperture 6 thereof. The cooling medium remains unmoved, i.e., stationary in the second area 3 of the cooling jacket whereby a rapid warm-up of the walls of the combustion spaces of the engine 1 is assured.

Due to the increasing warm-up of the cooling medium circulating in the closed circulation, the temperature thereof finally reaches the control temperature of the expansion element 38. The latter displaces its piston rod 38' outwardly whereby as a result of its support against the curved connecting member 47, the expansion element 38 itself is displaced in fact and after a slight idling or lost-motion movement opens by way of the curved draw member the by-pass disk valve 17 against the return force of the coil spring 49. The draw member .50 is thereby drivingly supported against the abutment 51 of the expansion element 38. As a result thereof, the cooling medium can flow into the interior of the housing 40 through the by-pass 11 in addition to the inlet through the connecting pipe stub 35 for the cooling medium line 35 whereby, according to FIG. 1, a through-flow also of the second area 3 of the cooling jacket of the engine 1 is established in the closed circulation without the inclusion of the radiator 9.

With a further increasing warm-up of the cooling medium, finally also the control temperature of the expansion element 18 is reached whereby also the piston rod 18' is displaced out of the expansion element 18. The piston rod 18 is thereby supported at the housing 40 by way of the member 41 and the valve seat 42 so that the expansion element 18 itself, together with the disk valve 16 secured thereon, lifts off from the valve seat 42 and opens up the cooling medium passage out of the return line 13 and the connecting stub 13" at the housing cover 40' through the radiator 9 with an increasing temperature.

However, due to the connection by way of connecting member 47 with the valve disk 16, also the connecting member 47, the expansion element 38 and the bypass disk valve 17 are displaced in unison with the disk valve 16 and the expansion element 18 so that the bypass 11 is again increasingly closed by the by-pass valve 17 with an increased opening of the disk valve 16. As

soon as the disk valve 17 comes into abutment, it can displace itself together with the draw member 50 against the force of the coil spring 49 relative to the expansion element 38 whereby the draw member 50 lifts off from the abutment 51 at the expansion element 38. With a closed by-pass 11, the cooling medium flows into the interior of the housing 40 through the connecting stub 35 for the cooling medium line 35 in the closed circulation through the first area 2 as also through the connecting stub 13" for the return line 13 in the housing cover 40' and through the opening of the disk valve 16 in a circulation containing the radiator 9 through the entire cooling jacket of the engine 1.

FIG. 5 illustrates a schematic view of a modified embodiment of a cooling system according to the present invention in which a three-way thermostat 115 is arranged at the branch place of the cooling medium line 8 leading to the radiator 9 and of the by-pass 11. Similar parts are thereby designated by similar reference numerals as used in FIGS. 1 to 4 and are therefore not described again.

Also, in this embodiment, the three-way thermostat 115 and the cooling medium valve 121 are combined into a structural unit within a common housing. However, it includes one disk valve 116 and 117 each as well as one expansion element 118 and 138 each. The mixing place 14 of the return line 13 with the by-pass 11 which is arranged, like the branching place 10, also in the common housing of the three-way thermostat 115 and of the cooling medium valve 121, thereby includes the expansion element 138 of the cooling medium valve 121. The circulation line 19 terminates already upstream of the cooling medium valve 121 in the return line 13 of the radiator 9.

The disk valves 116 and 117 assume in FIG. 5 with a cold cooling medium the full-line position and are both closed. The cold cooling medium thus circulates exclusively in the closed circulation through the first area 2 of the cooling jacket of the engine 1. It leaves by way of the discharge aperture 6, flows through the circulation line 19 and the heater heat-exchanger 20, terminates in the return line 13 and flows through the cooling medium valve 121 before it is again fed by the cooling medium pump 12 through the inlet aperture 4 into the first area 2 of the cooling jacket. The cooling medium, in addition to flowing through the circulation line 19, also flows through the parallel circulation line 24 and as a result thereof, the heater jacket 25 of the suction line throttle valve 26 as well as the temperature pick-up 27 for a fuel metering device of the engine are acted upon thereby.

In the cooling medium valve 121, the increasing warming-up cooling medium over the expansion element 138 thereof, after which reaching its control temperature actuates the disk valve 117 into the open position thereof illustrated in dash line. As a result thereof, a' cooling medium circulation commences also through the bypass l1 and thus through the second area 3 of the cooling jacket, the discharge aperture 5 thereof and the three-way thermostat 115 at thebranch place 10. The closed disk valve 116 continues to prevent a cooling medium flow to the radiator 9 up to the warm-up of the cooling medium disposed in the closed circulation to the control temperature of the expansion element 118. As soon as the control temperature of the expansion element 118 is exceeded, the disk valve 116 opens with simultaneous continuous reclosing of the by-pass 11 by means of the disk valve 117. The latter is displaced against this valve seat by the displacement of the expansion element 118. Suitable support means and spring means as well as bearing support means enable a construction of these parts satisfying the operation thereof, for example, by utilizing the teachings of the construction according to FIG. 4. Due to an alternate continuous opening and closing of the disk valves 116 and 117 and corresponding inclusion of the radiator 9 into the cooling medium circulation, the operating temperature of the engine is controlled in the usual manner.

While we have shown and described several embodiments in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to those skilled in the art, and we therefore do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

What we claim is:

1. A circulatory cooling installation for piston internal combustion engines having combustion zones, the installation comprising a cooling jacket means and a control means which is operable to interrupt the cooling medium circulation through the cooling jacket means at least within the area of the combustion zones up to a predetermined first limit value, which above the first predetermined limit value is operable to limit the circulation at first to a closed circulation in by-passing relationship to a radiator and under avoidance of a fresh water exchange, and which above a further predetermined limit value is operable to include into the cooling medium circulation at least one of radiator, fresh water exchange and a heater heat-exchanger means, characterized in that the control means includes in effect a cooling medium valve means and a three-way thermostat means each having a separate control element, of which the cooling medium valve means is actuated upon reaching the first limit value and the three-way thermostat means is actuated upon reaching the further limit value.

2. An installation according to claim 1, characterized in that the predetermined first limit value is a predetermined temperature limit value of the engine.

3. An installation according to claim 1, characterized in that the first predetermined limit value is a predetermined value of the time after the starting of the engine.

4. An installation according to claim 3, characterized in that the predetermined first limit value is a predetermined temperature limit value of the engine.

5. An installation according to claim 1, characterized in that above the further predetermined limit value, the radiator is incorporated in the cooling medium circulation.

6. An installation according to claim 5, characterized in that above the further predetermined limit value at least one of the two parts consisting of heater heatexchanger means and fresh water exchange are additionally incorporated in the cooling medium circulation.

7. An installation according to claim 6, characterized in that both of said parts are incorporated in the cooling medium circulation above said further predetermined limit value.

8. An installation according to claim 1, characterized in that the cooling medium valve means and the threeway thermostat means are combined in a common thermostat housing means.

9. An installation according to claim 8, characterized in that the cooling medium valve means below the predetermined limit value additionally closes the cooling medium passage opened by the three-way theremostat means below the predetermined temperature limit value.

10. An installation according to claim 9, characterized in that the last-mentioned cooling medium passage is a by-pass.

11. An installation according to claim 8, characterized in that the cooling medium valve means and the three-way thermostat means include disk valve means, temperature-sensing sensing means and aperture means for the cooling medium-valve-means and the three-way thermostat means which are arranged substantially coaxially.

12. An installation according to claim 1 1, in which up to the first limit value at least one throttled cooling medium circulation exists in the cooling jacket means within the area outside of the combustion zones, characterized in that a cooling medium inlet and discharge aperture means for the full cooling circulation are provided in conventional places and a cooling medium discharge for the closed circulation is provided at a place near the cooling medium inlet aperture means in the area outside the combustion zones in the cooling jacket means.

13. An installation according to claim 12, characterized in that at least one of space heater means, suction pipe heater means and temperature pick-up means for auxiliary devices of the internal combustion engine are arranged in the closed cooling medium circulation.

14. An installation according to claim 13, characterized in that the space heater means is a heater heatexchanger and the suction pipe heater means is a heating jacket.

15. An installation according to claim 12, characterized in that a space heater means, a suction pipe heater means and temperature pick-up means are arranged in the closed cooling medium circulation.

16. An installation according to claim 12, characterized in that the temperature sensing means of the cooling medium valve means is acted upon by the cooling medium of the closed circulation.

17. An installation according to claim 16, characterized in that the temperature sensing means is an expansion element.

18. An installation according to claim 17, characterized in that the cooling medium valve means and a disk valve of the three-way thermostat means controlling the cooling medium circulation from the second area of the cooling jacket means to the cooling jacket inlet are combined into a single by-pass disk valve which is actuated by the temperature sensing means of the three-way thermostat means and the temperature sensing means of the cooling medium valve means.

19. An installation according to claim 18, characterized in that the cooling medium valve means and the three-way thermostat means are arranged in a common housing means with two mutually coaxially oppositely disposed disk valves, and in that the two temperature sensing means with the disk valves secured thereon and with mutually opposite thermostat inlet aperture means are arranged substantially coaxially.

20. An installation according to claim 19, characterized in that a first expansion element operable as temperature sensing means carries a first valve disk of the three-way thermostat means and includes a piston rod supported at the housing means, and in that additionally said first-mentioned expansion element is operatively connected with a second expansion element which axially adjusts the second common valve disk of the three-way thermostat means and of the cooling valve means with respect to the first valve disk.

21. An installation according to claim 20, characterized in that the second-mentioned expansion element is axially adjustably guided with respect to the firstmentioned valve disk and is drivingly connected with the second valve disk, the piston rod of the second expansion element being supported at the first valve disk.

22. An installation according to claim 21, characterized in that the second valve disk is acted upon in the closing direction by a coil spring which is supported against a connecting member secured at the first valve disk, and is operatively connected with the second expansion element by a connecting means which is slidingly guided at one of the two parts consisting of the second valve disk and the second expansion element, supported against an abutment in the direction of movement.

23. An installation according to claim 8, characterized in that the cooling medium valve means below the predetermined limit value additionally closes the cooling medium passage opened by the three-way thermostat means below the predetermined temperature limit value whereby a cooling medium from the closed circulation acts upon the temperature sensing means of the cooling medium valve means.

24. An installation according to claim 23, characterized in that the last-mentioned closed circulation terminates in the return line.

25. An installation according to claim 23, characterized in that the last-mentioned closed circulation terminates either upstream of or at a place at which is located the temperature-sensing means of the cooling medium valve means.

26. An installation according to claim 1, characterized in that a cooling medium pump means operable to be turned ofi up to reaching the first limit value is provided in lieu of the cooling medium valve means.

27. An installation according to claim 1, characterized in that the cooling medium valve means below the predetermined limit value additionally closes the cooling medium passage opened by the three-way thermostat means below the predetermined temperature limit value.

28. An installation according to claim 27, characterized in that the last-mentioned cooling medium passage is a by-pass.

29. Aninstallation according to claim 1, characterized in that the cooling medium valve means and the three-way thermostat means include disk valve means, temperature-sensing means and aperture means for the cooling medium-valve-means and the three-way thermostat means which are arranged substantially coaxially.

30. An installation according to claim 29, characterized in that the parts of the cooling medium valve means and the three-way thermostat means are arranged in a common thermostat housing means.

31. An installation according to claim 1, in which up to the first limit value at least one throttled cooling medium circulation exists in the cooling jacket means within the area outside of the combustion zones, characterized in that a cooling medium inlet and discharge aperture means for the full cooling circulation are provided in conventional places and a cooling medium discharge for the closed circulation is provided at a place near the cooling medium inlet aperture means in the area outside the combustion zones in the cooling jacket means.

32. An installation according to claim 31, characterized in that at least one of space heater means, suction pipe heater means and temperature pick-up means for auxiliary devices of the internal combustion engine are arranged in the closed cooling medium circulation.

33. An installation according to claim 32, characterized in that the space heater means is a heater heatexchanger and the suction pipe heater means is a heating jacket.

34. An installation according to claim 31, characterized in that a space heater means, a suction pipe heater means and temperature pick-up means are arranged in the closed cooling medium circulation.

35. An installation according to claim 31, with temperature sensing means for the cooling medium valve means, characterized in that the temperature sensing means of the cooling medium valvev means is acted upon by the cooling medium of the closed circulation.

36. An installation according to claim 35, characterized in that the temperature sensing means is an expansion element.

37. An installation according to claim 29, characterized in that the cooling medium valve means and a disk valve of the three-way thermostat means controlling the cooling medium circulation from the second area of the cooling jacket means to the cooling jacket inlet are combined into a single by-pass disk valve which is actuated by temperature sensing means of the threeway thermostat means and the temperature sensing means of the cooling medium valve means.

38. An installation according to claim 37, characterized in that the cooling medium valve means and the three-way thermostat means are arranged in a common housing means with two mutually coaxially oppositely disposed disk valves, and in that the two temperature sensing means with the disk valves secured thereon and with mutually opposite thermostat inlet aperture means are arranged substantially coaxially.

39. An installation according to claim 38, characterized in that a first expansion element operable as temperature sensing means carries a first valve disk of the three-way thermostat means and includes a piston rod supported at the housing means, and in that additionally said first-mentioned expansion element is operatively connected with a second expansion element which axially adjusts the second common valve disk of the three-way thermostat means and of the cooling valve means with respect to the first valve disk.

40. An installation according to claim 39, characterized in that the second-mentioned expansion element is axially adjustably guided with respect to the firstmentioned valve disk and is drivingly connected with the second valve disk, the piston rod of the second expansion element being supported at the first valve disk.

41. An installation according to claim 40, characterized in that the second valve disk is acted upon in the closing direction by a coil spring which is supported against a connecting member secured at the first valve disk, and is operatively connected with the second expansion element by a connecting means which is slidingly guided at one of the two parts consisting of the second valve disk and the second expansion element, supported against an abutment in the direction of movement. 

1. A circulatory cooling installation for piston internal combustion engines having combustion zones, the installation comprising a cooling jacket means and a control means which is operable to interrupt the cooling medium circulation through the cooling jacket means at least within the area of the combustion zones up to a predetermined first limit value, which above the first predetermined limit value is operable to limit the circulation at first to a closed circulation in by-passing relationship to a radiator and under avoidance of a fresh water exchange, and which above a further predetermined limit value is operable to include into the cooling medium circulation at least one of radiator, fresh water exchange and a heater heat-exchanger means, characterized in that the control means includes in effect a cooling medium valve means and a three-way thermostat means each having a separate control element, of which the cooling medium valve means is actuated upon reaching the first limit value and the three-way thermostat means is actuated upon reaching the further limit value.
 2. An installation according to claim 1, characterized in that the predetermined first limit value is a predetermined temperature limit value of the engine.
 3. An installation according to claim 1, characterized in that the first predetermined limit value Is a predetermined value of the time after the starting of the engine.
 4. An installation according to claim 3, characterized in that the predetermined first limit value is a predetermined temperature limit value of the engine.
 5. An installation according to claim 1, characterized in that above the further predetermined limit value, the radiator is incorporated in the cooling medium circulation.
 6. An installation according to claim 5, characterized in that above the further predetermined limit value at least one of the two parts consisting of heater heat-exchanger means and fresh water exchange are additionally incorporated in the cooling medium circulation.
 7. An installation according to claim 6, characterized in that both of said parts are incorporated in the cooling medium circulation above said further predetermined limit value.
 8. An installation according to claim 1, characterized in that the cooling medium valve means and the three-way thermostat means are combined in a common thermostat housing means.
 9. An installation according to claim 8, characterized in that the cooling medium valve means below the predetermined limit value additionally closes the cooling medium passage opened by the three-way theremostat means below the predetermined temperature limit value.
 10. An installation according to claim 9, characterized in that the last-mentioned cooling medium passage is a by-pass.
 11. An installation according to claim 8, characterized in that the cooling medium valve means and the three-way thermostat means include disk valve means, temperature-sensing sensing means and aperture means for the cooling medium-valve-means and the three-way thermostat means which are arranged substantially coaxially.
 12. An installation according to claim 11, in which up to the first limit value at least one throttled cooling medium circulation exists in the cooling jacket means within the area outside of the combustion zones, characterized in that a cooling medium inlet and discharge aperture means for the full cooling circulation are provided in conventional places and a cooling medium discharge for the closed circulation is provided at a place near the cooling medium inlet aperture means in the area outside the combustion zones in the cooling jacket means.
 13. An installation according to claim 12, characterized in that at least one of space heater means, suction pipe heater means and temperature pick-up means for auxiliary devices of the internal combustion engine are arranged in the closed cooling medium circulation.
 14. An installation according to claim 13, characterized in that the space heater means is a heater heat-exchanger and the suction pipe heater means is a heating jacket.
 15. An installation according to claim 12, characterized in that a space heater means, a suction pipe heater means and temperature pick-up means are arranged in the closed cooling medium circulation.
 16. An installation according to claim 12, characterized in that the temperature sensing means of the cooling medium valve means is acted upon by the cooling medium of the closed circulation.
 17. An installation according to claim 16, characterized in that the temperature sensing means is an expansion element.
 18. An installation according to claim 17, characterized in that the cooling medium valve means and a disk valve of the three-way thermostat means controlling the cooling medium circulation from the second area of the cooling jacket means to the cooling jacket inlet are combined into a single by-pass disk valve which is actuated by the temperature sensing means of the three-way thermostat means and the temperature sensing means of the cooling medium valve means.
 19. An installation according to claim 18, characterized in that the cooling medium valve means and the three-way thermostat means are arranged in a common housing means with two mutually coaxially oppositely disposed disk valves, and in that the two temperature sensing means with the disk vAlves secured thereon and with mutually opposite thermostat inlet aperture means are arranged substantially coaxially.
 20. An installation according to claim 19, characterized in that a first expansion element operable as temperature sensing means carries a first valve disk of the three-way thermostat means and includes a piston rod supported at the housing means, and in that additionally said first-mentioned expansion element is operatively connected with a second expansion element which axially adjusts the second common valve disk of the three-way thermostat means and of the cooling valve means with respect to the first valve disk.
 21. An installation according to claim 20, characterized in that the second-mentioned expansion element is axially adjustably guided with respect to the first-mentioned valve disk and is drivingly connected with the second valve disk, the piston rod of the second expansion element being supported at the first valve disk.
 22. An installation according to claim 21, characterized in that the second valve disk is acted upon in the closing direction by a coil spring which is supported against a connecting member secured at the first valve disk, and is operatively connected with the second expansion element by a connecting means which is slidingly guided at one of the two parts consisting of the second valve disk and the second expansion element, supported against an abutment in the direction of movement.
 23. An installation according to claim 8, characterized in that the cooling medium valve means below the predetermined limit value additionally closes the cooling medium passage opened by the three-way thermostat means below the predetermined temperature limit value whereby a cooling medium from the closed circulation acts upon the temperature sensing means of the cooling medium valve means.
 24. An installation according to claim 23, characterized in that the last-mentioned closed circulation terminates in the return line.
 25. An installation according to claim 23, characterized in that the last-mentioned closed circulation terminates either upstream of or at a place at which is located the temperature-sensing means of the cooling medium valve means.
 26. An installation according to claim 1, characterized in that a cooling medium pump means operable to be turned off up to reaching the first limit value is provided in lieu of the cooling medium valve means.
 27. An installation according to claim 1, characterized in that the cooling medium valve means below the predetermined limit value additionally closes the cooling medium passage opened by the three-way thermostat means below the predetermined temperature limit value.
 28. An installation according to claim 27, characterized in that the last-mentioned cooling medium passage is a by-pass.
 29. An installation according to claim 1, characterized in that the cooling medium valve means and the three-way thermostat means include disk valve means, temperature-sensing means and aperture means for the cooling medium-valve-means and the three-way thermostat means which are arranged substantially coaxially.
 30. An installation according to claim 29, characterized in that the parts of the cooling medium valve means and the three-way thermostat means are arranged in a common thermostat housing means.
 31. An installation according to claim 1, in which up to the first limit value at least one throttled cooling medium circulation exists in the cooling jacket means within the area outside of the combustion zones, characterized in that a cooling medium inlet and discharge aperture means for the full cooling circulation are provided in conventional places and a cooling medium discharge for the closed circulation is provided at a place near the cooling medium inlet aperture means in the area outside the combustion zones in the cooling jacket means.
 32. An installation according to claim 31, characterized in that at least one of space heater means, suction pipe heater means and tempErature pick-up means for auxiliary devices of the internal combustion engine are arranged in the closed cooling medium circulation.
 33. An installation according to claim 32, characterized in that the space heater means is a heater heat-exchanger and the suction pipe heater means is a heating jacket.
 34. An installation according to claim 31, characterized in that a space heater means, a suction pipe heater means and temperature pick-up means are arranged in the closed cooling medium circulation.
 35. An installation according to claim 31, with temperature sensing means for the cooling medium valve means, characterized in that the temperature sensing means of the cooling medium valve means is acted upon by the cooling medium of the closed circulation.
 36. An installation according to claim 35, characterized in that the temperature sensing means is an expansion element.
 37. An installation according to claim 29, characterized in that the cooling medium valve means and a disk valve of the three-way thermostat means controlling the cooling medium circulation from the second area of the cooling jacket means to the cooling jacket inlet are combined into a single by-pass disk valve which is actuated by temperature sensing means of the three-way thermostat means and the temperature sensing means of the cooling medium valve means.
 38. An installation according to claim 37, characterized in that the cooling medium valve means and the three-way thermostat means are arranged in a common housing means with two mutually coaxially oppositely disposed disk valves, and in that the two temperature sensing means with the disk valves secured thereon and with mutually opposite thermostat inlet aperture means are arranged substantially coaxially.
 39. An installation according to claim 38, characterized in that a first expansion element operable as temperature sensing means carries a first valve disk of the three-way thermostat means and includes a piston rod supported at the housing means, and in that additionally said first-mentioned expansion element is operatively connected with a second expansion element which axially adjusts the second common valve disk of the three-way thermostat means and of the cooling valve means with respect to the first valve disk.
 40. An installation according to claim 39, characterized in that the second-mentioned expansion element is axially adjustably guided with respect to the first-mentioned valve disk and is drivingly connected with the second valve disk, the piston rod of the second expansion element being supported at the first valve disk.
 41. An installation according to claim 40, characterized in that the second valve disk is acted upon in the closing direction by a coil spring which is supported against a connecting member secured at the first valve disk, and is operatively connected with the second expansion element by a connecting means which is slidingly guided at one of the two parts consisting of the second valve disk and the second expansion element, supported against an abutment in the direction of movement. 